The present invention relates to a ceramic composition which is particularly well suited for quick firing, consisting mainly of a lime component, a clay component, and water, and a method for manufacturing the ceramic compound and its utilization for manufacturing stoneware products.
Various kinds of stoneware compositions for lime or feldspar stoneware are produced in large quantities for the manufacturing of ceramic products, especially wall tiles and crockery. Clays, quartz powder, calcareous spars and fluxing materials such as feldspars, syenites etc. are generally used as main raw materials. These stoneware compounds are fired at temperatures of approximately 1000.degree.-1100.degree. C. They must be heated slowly and fired over a long period of time. A common firing period is about 24 hours.
To reduce the long firing periods, many attempts have been made during the last few years within the ceramic industry to develop a composition suitable for quick firing. In the wall tile industry in America, compositions which are suitable for quick firing are manufactured on the basis of clay-wollastonite or clay-talc-dolomite. In Germany, and also in Middle Europe, such compositions are not utilized, as no suitable raw materials are available, i.e. there are no local deposits of wollastonite and talc. Attempts have been made to synthesize wollastonite or other calcium silicates (e.g. diopside) and use these as raw materials in the ceramic industry. The types of compositions manufactured by synthetic wollastonite have very good qualities with regard to quick firing. Within the wall tile industry, however, wollastonite has not been used as a raw material in quantities worth mentioning, as wollastonite is too expensive for such use.
It is an object of the present invention to provide a ceramic composition especially suitable for quick firing and for manufacturing stoneware, using a cheap raw material.
It is a further object of the invention to provide a method of making such ceramic composition and yet a further object is to provide a method of making stoneware therefrom.